I want to get a Big Gun silencer for my 300 ex but Big Gun doesn't make a head pipe for it. I was wondering which head pipe would be best to go with it?later

 

If the Big Gun will bolt to a stock headpipe, and a Poweroll oversized headpipe will replace a stock headpipe, then 1 + 2 = 3 and you should be able to use a Poweroll headpipe and a Big Gun silencer.
Ride hard and have fun, 300EX-treme

 

so you think the Poweroll head pipe is the best you can buy?